Road death warnings are killing drivers, research finds

A road safety campaign in the US appears to have had the tragic effect of causing more deaths.

Researchers found that overhead signs on Texas highways which remind drivers of the mounting annual death toll from road traffic incidents were inadvertently leading to more crashes.

The “in-your-face” approach can weigh on the mind of a passing driver and temporarily dull their ability to respond to what is happening on the road, the researchers found.

The study, authored by Professor Jonathan Hall from the University of Toronto and Joshua Madsen of the University of Minnesota, observed crash data before and after warning signs were introduced in Texas.

The Texas Department of Transportation displayed the state-wide traffic death toll for the year so far on digital road signs for one week of each month as part of a driving safety awareness campaign.

A review of the crash data found there were more fatalities in the weeks when the death toll messages were displayed. The number of fatalities in the 10km after a digital road sign was found to be 4.5 per cent higher when drivers were warned of the death toll.

This increase was comparable to raising the speed limit by 3 to 5 mph or reducing roadside police officers by 6 to 14 per cent, according to previous research.

The researchers said their findings suggest the signs caused an additional 2,600 crashes and 16 deaths per year in Texas, costing $377m (£293m) each year.

Prof Hall told The Independent: “We were surprised to find that these safety messages actually caused more crashes. We believe the signs cause more crashes because they distract drivers.”

In a sign that the emotional weight of the messaging stuck with drivers, researchers found the bigger the number in the fatality message, the more harmful the effects.

The number of additional crashes each month increased as the death toll rose throughout the year, with the most additional crashes occurring in January when the message stated the annual total. Deaths were also higher at points when drivers had more to be aware, such as in heavy traffic or on complex sections of road.

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“The messages also increased the number of multi-vehicle crashes, but not single-vehicle crashes,” said Prof Hall. “This is in line with drivers with increased cognitive loads making smaller errors due to distraction, like drifting out of a lane, rather than driving off the road.”

However, the researchers found there was a reduction in crashes when the displayed death tolls were low and when the messages appeared on less complex sections of road.

Prof Madsen said this suggests that there were times when the messaging was not as taxing on drivers’ attention.

But he said agencies should nonetheless consider alternative ways to raise awareness.

“Distracted driving is dangerous driving,” said Prof Madsen. “Perhaps these campaigns can be reimagined to reach drivers in a safer way, such as when they are stopped at an intersection, so that their attention while driving remains focused on the roads.”

The research was supported by the Social Sciences and Humanities Research Council of Canada and the European Union’s Horizon 2020 research and innovation programme. Their findings were published in the Science journal.